The disclosures of Dr. Abbott claim a special importance among the fruits of archæological investigation on the American continent, not only from the fact that they furnish the first well-authenticated results of systematic research based on the scientific analogies of European archæology, but these later results have included the remains of man himself. When Dr. Usher of Mobile contributed to _The Types of Mankind_ an account of the discovery of a human skeleton at New Orleans, found under circumstances from which the existence of man in the delta of the Mississippi was deduced well nigh sixty thousand years ago, it was scarcely calculated to win the reader’s acceptance of that assumption when it was added that “the type of the cranium was, as might have been expected, that of the aboriginal American race.” Nor is this the only example of skull of a strictly modern Indian type from which the inference has been drawn that the same unchanging form has prevailed from the era of pre-glacial American man till now. Three human crania found in the Trenton gravel are now in the Peabody Museum at Cambridge (Harvard). All are of the same type, but it differs essentially from that of the Red Indian skull. They are of small size, oval, and present a striking contrast to all other skulls in the Peabody collection. Their value is due to the fact of their discovery in the implement-bearing gravel, in proximity to the characteristic examples of what are assumed to be palæolithic celts. For it is well for us to bear in remembrance that the evidences of the antiquity of man in Europe do not rest on any number of chance disclosures. It is a simple procedure to dig into a Celtic or Saxon barrow, and find there the implements and pottery of its builders lying alongside of their buried remains. But archæologists have learned to recognise the palæolithic implements as not less characteristic of certain post-pliocene deposits than the palæontology of the same geological formation. The river-drift and cave deposits are characterised by traces of contemporaneous life, as shown in the examples of primitive art from which they receive the name of the tool-bearing drift or gravel; just as older geological formations have their characteristic animal and vegetable fossils. The specific character of the tool-bearing gravel of the French Drift having been determined, geologists and archæologists have sought for flint implements in corresponding English strata, as they would seek for the fossils of the same period, and with like success. Palæolithic implements have been recovered in this manner in Suffolk, Bedford, Hartford, Kent, Middlesex, Surrey, and other districts in the south of England. So entirely indeed has the man of the Drift passed beyond the province of the archæologist, that in 1861 Professor Prestwich followed up his _Notes on Further Discoveries of Flint Implements in Beds of Post-Pleiocene Gravel and Clay_, with a list of forty-one localities